1. Field of the Invention
This invention relates to burglar alarms. More particularly, it relates to a non-electrical bell adapted to be affixed to a door in such a manner that it sounds when the door is opened.
2. Description of the Prior Art
Numerous door burglar alarms are known which are adapted to sound when a door is opened. However, such alarms are generally of complex structure, require electrical connections and must be disconnected when someone is at home during daylight hours.